In the innocent, bygone days of February, President Obama told NBC News that the campaign would get negative against him, but provided this assurance: “I think that you will be able to see how we conduct ourselves in the campaign. I think it will be consistent with how I conducted myself in 2008 and hopefully how I have conducted myself as president of the United States.”

Not since Gary Hart urged reporters to follow him around because “they’d be very bored” has an assurance been more of an indictment. The Obama campaign has targeted and intimidated Republican donors on an Internet enemies list. It has engaged in the juvenile mockery of Mitt Romney’s singing. It has suggested, without evidence, that Romney may have committed the felony of falsifying Federal Election Commission documents. It has speculated, without proof, that Romney has avoided paying taxes. When Joe Biden engages in racially charged hyperbole, he is awkwardly but accurately reflecting the spirit of the 2012 Obama campaign.

But the most vivid accusation (made by a closely associated PAC and embraced by the campaign itself) is that Romney’s ruthless business practices were responsible for the closing of a firm, the loss of a couple’s health insurance and thus the death of a woman from cancer. Except that Romney wasn’t connected to the closing of the firm, the woman continued to have health insurance from another source and her cancer was diagnosed five years after the plant shut down.

Which represents the crossing of an ethical line. If the conduct of the Obama campaign team were universalized, candidates would no longer require any evidence to accuse one another of complicity in a death. To accept this as a new political norm would be to define defamation down.

Obama’s defenders assure us that everyone does it. But not everyone does this. It is one thing to exploit a misstatement; another to exploit a tragedy. It is one thing to mischaracterize a federal waiver; another to accuse an opponent of being the Angel of Death.

For the Obama campaign, this is not an aberration; it is a culmination. The demonization of Romney is a main element of its strategy, pursued by Obama’s closest associates and former employees, not by loosely affiliated partisan groups. Deniability is not even remotely plausible, but it doesn’t remotely matter. Even when exposed, the Obama campaign never retracts, never apologizes — convinced that the news cycle will quickly erase inconvenient memories.

It seems to be working, at least for the moment. Obama’s recent polling gains are mainly explainable by Romney’s rising negatives, particularly among independents. Even as political journalists point out distortions by the Obama campaign, they tend to praise its boldness, coordination and momentum. And each new controversy succeeds in distracting attention from Obama’s economic stewardship.

There is, however, some collateral damage. Obama increased the turnout of young voters in 2008 by more than 2 million over the previous election. But the level of trust by young people in public institutions, including the presidency, has been declining. Youth interest in politics has waned. Some of this is a function of understandable economic discontent. But apart from the most partisan, what young voters have had their sights and spirits lifted by the current campaign? Having introduced a generation to political idealism, Obama seems intent on taking it back.

Ronald Reagan expressed distrust of government while paradoxically improving its image and standing. Obama has placed boundless faith in government while trust in public institutions has declined to all-time lows. It is the legacy of Obama’s liberalism: expanding the state while helping discredit the political process.

The Obama campaign is veering toward antinomianism. Since it regards its own motives as pure, it feels it can dispense with the normal rules of accuracy, civility and decency. So we get the political methods of Spiro Agnew combined with the moral self-regard of Woodrow Wilson. It is not an attractive mixture.

Speaking in Canton, Ohio, a week before the 2008 election, Obama said, “Some of you may be cynical and fed up with politics. A lot of you may be disappointed and even angry with your leaders. You have every right to be. But despite all of this, I ask of you what has been asked of Americans throughout our history. I ask you to believe.”

I am admittedly a sucker for rhetorical idealism. But it can’t be a small thing, a typical thing, a trivial thing, to ask for belief and then betray it.